This invention generally pertains to a multifunctional field implement useful in the practice of conservation tillage of the type which reduces soil disturbance and leaves a protective mulch of crop residue on the soil surface.
It is well established that bare, smooth soil left by clean moldboard plowing and intensive secondary tillage is extremely susceptible to water and wind erosion. Such erosion permanently removes that layer of soil and accompanying nutrients which are most favorable for crop growth. Thereafter, these natural nutrients must be replaced with costly added fertilizer in order to maintain yields and land values. Runoff from eroding fields may carry a variety of chemical pollutants and substantial quantities of sedimentary materials into streams, rivers and ponds thereby biologically degrading the quality of our fresh water supply and reducing the storage capacity of lakes and reservoirs. This threat to the nation posed by soil erosion and water pollution resulting from long standing farming method has resulted in the U.S. Department of Agriculture formulating practices which future recipients of certain farm subsidies and payments must adopt in connection with controlling erosion and pollution levels resulting from the recipient's farming operations.
The potential for irreversible loss of agricultural land base, unacceptable levels of water and air pollution and the prospect of governmental sanctions are causing increased numbers of farmers to adopt a conservation tillage practice whereby a new crop is planted directly in the stalks and stubble remaining from the previous harvested crop. Seed is planted in undisturbed ground by a special seed drill equipped to plant through residue lying upon firm soil. This conservation tillage system which greatly reduces soil disturbance and leaves the crop residue on the soil surface is commonly referred to as the "no-till" system of farming.
Generally, the no-till system entails applying plant nutrients on the soil surface prior to planting and pre-emergence herbicides are applied after planting to control weeds and grasses.
Some of the general advantages of no-till farming are as follows:
Crop residues serve to reduce runoff of excess rain-water even on substantial slopes; PA1 Because crop residues reduce water runoff, they tend to hold plant nutrients and applied fertilizers in place with a concomitant reduction in pollution of downstream water sources; PA1 Crop residues slow and break up wind currents at the soil surface thereby reducing soil partical erosion; PA1 Crop residues contacting the soil reduce evaporation thereby conserving soil moisture for use by the crop; and, PA1 Power and labor costs are considerably lower than those required by conventional tillage systems which loosen top soil and turn under some or all of the crop residue. PA1 Flatten and chop crop stalks and stems in segments of selectively variable size. PA1 Aerate the soil by means of ground opening discs. PA1 Place a metered quantity of fertilizer in a plurality of furrows formed by the action of the ground-opening discs. PA1 Hoe a portion of the soil displaced from the furrow together with surface residues back into the furrow into close contact with the fertilizer previously placed therein.
In conjunction with no-till farming, it is desirable to knock down and chop up the stalks and stems left standing in a field in order to facilitate the application of fertilizer and to place more of the crop residue in direct contact with the ground. Thus broadcasting of fertilizer over a no-till field is easier and more even if the large stalks of crops, such as corn, are flattened first. By chopping the stalks and stems into smaller segments, direct contact with the soil is more likely and more rapid decomposition of such organic residue, hence their conversion to plant nutrients, is facilitated.
Many farmers who have adopted the no-till system find that applying dry, granular commercial fertilizer compounds in the Fall of the year is best suited to their schedule for field work and reduces the risk that a rainy Spring season will interfer with fertilizer application at that time. Advantages have been found in placing dry fertilizer in bands at shallow depths and covering the same rather than broadcasting the fertilizer granuals on top of the crop residue. It is also believed that some degree of Fall soil aeration beyond that contemplated by conventional no-till practice permits moisture penetration, reduces water runoff and promotes the growth of organisms which produce rapid decomposition of crop residues.
While residue choppers, subsoil fertilizer banders and soil aerators are to be found as separate implements and could be used in successive operations, it is believed that no composite implement has heretofore been designed to provide all of these functions in a single trip over a no-till field. Therefore, a more universal adoption of no-till practices may yet today be impeded by the unattractive prospects of investing substantial capital in a plurality of costly implements and of incurring repetitious operating expenses in the Fall season preparation of a field for no-till Spring season planting.